Integrated pressure compensating heat exchanger and method

ABSTRACT

An integrated pressure compensating heat exchanger and method of use are provided. The integrated pressure compensating heat exchanger includes an inlet configured to input an internal fluid; a first conductive bellows connected to the inlet, configured to accept the internal fluid from the inlet, configured to transfer heat between the internal fluid and an external fluid, and configured to compensate for a pressure by compressing in length; and an outlet configured to accept the internal fluid from the first conductive bellows and to output the internal fluid.

BACKGROUND OF THE INVENTION

Embodiments of the subject matter disclosed herein generally relate tomethods and devices and, more particularly, to integrated pressurecompensating heat exchangers and methods for using same in electricengines connected to compressors.

During the past years, the importance of large electric engines invarious industries has increased. For example, large electric enginesare used to drive turbo-machinery used in power generation, cryogenicapplications, oil and gas refining, petrochemistry, etc. Specifically, alarge electric engine may be connected to a compressor.

These electric engines produce a great deal of heat internally due toelectrical resistance in the windings. Typically these electric enginesare cooled (and also electrically insulated) by a fluid such as oilwhich gets hot by absorbing heat from the windings. Then the hot oilitself is cooled by another fluid (such as ambient air) in a heatexchanger.

One problem is that the oil expands as its temperature increases, and apressure compensator is required to compensate for the increased volumeof the oil. Oil is a relatively incompressible fluid, and increases intemperature in a fixed volume (such as in a cavity inside of a sealedelectric motor) and will cause tremendous increases in pressure whichmay blow out a seal or even catastrophically explode the electric motor.Therefore, a pressure compensator is essential, in addition to the heatexchanger. The pressure compensator may use a bellows or a piston tocompensate for changes in volume of the oil in order to maintain a safepressure. Thus, the electric engine requires a heat exchanger, and alsorequires a pressure compensator.

A second problem is that the heat exchanger and pressure compensator areconventionally distinct and separate devices (in other words, thesedevices are not integrated). Distinct devices require more parts, andmore parts increase the cost and decrease the reliability.

A third problem is that the pressure compensator is conventionallylocated outside of the electric motor. This external location requiresat least one additional opening or passage in the electric motor toroute the oil to and from the pressure compensator. Furthermore, thisexternal location requires some external mounting mechanism for thepressure compensator, exposes the pressure compensator to the risk ofmechanical damage from external physical events, and exposes thepressure compensator to external chemical attack (such as corrosion fromsalt water). Also, the external location exposes the pressurecompensator to external temperature fluctuations.

Additional problems caused by conventional designs include: requiring alarge heat exchanger; requiring very precise temperature and pressurecontrol; requiring many additional parts due to not being integrated;being overly sensitive to ambient temperature fluctuations; requiringcomplex plant couplings; and not allowing standardization.

FIG. 1 is a conventional heat exchanger assembly 2 includingnon-conductive bellows 16. Specifically, an external fluid 4 passes overtubes 10, and exchanges heat with an internal fluid 6 through the wallsof tubes 10. The internal fluid 6 enters inlet elbow 8, passes throughan inlet non-conductive bellows 16, passes through a series of tubes 10and U-shaped adaptors 39, passes through an outlet non-conductivebellows 16, and finally exits through an outlet elbow 14. The term“non-conductive bellows” indicates that the non-conductive bellows isnot located in a flow path of the external fluid, and therefore is notconfigured to conduct heat between the external fluid and the internalfluid.

Additionally, a spring mechanism 18 includes a spring 20 which maintainsspring pressure against a U-shaped adaptor 39. This spring pressurekeeps the U-shaped adaptor 39 squeezed against the tubes 110 in order tomaintain a seal between the U-shaped adaptor 39 and the tubes 10, andthereby working as an expansion joint. In FIG. 1, it appears that thenon-conductive bellows 16 are primarily used to accommodate the physicalmovement of the U-shaped adaptors 39 in response to the horizontalthermal expansion of the tubes 10.

FIG. 1 (described above) is derived from the first figure of Hoffmüller(U.S. Pat. No. 4,328,680, the entire content of which is incorporatedherein by reference). Note that Hoffmüller uses the term “expansionpressure device” in the Abstract regarding accommodating the axial(longitudinal) thermal expansion of the heat exchanger tubes, and doesnot address compensating fluid pressure caused by volumetric increasesof heat transfer fluids due to temperature increases.

Neary et al. (U.S. Pat. No. 3,527,291, the entire content of which isincorporated herein by reference) discloses an expansion joint 22including a non-conductive bellows 23 located directly between (andpassing internal fluid between) a heater tube 18 and a header pipe 12 atFIG. 3 of Neary. The explicit purpose of the non-conductive bellows 23in Neary is for “preventing tube buckling by accommodating tubeexpansion,” as stated at column 1, lines 24-45 of Neary.

Byrne (U.S. Pat. No. 4,246,959, the entire content of which isincorporated herein by reference) discloses a flexible metalnon-conductive bellows 32 in FIG. 2 of Byrne. The explicit purpose ofthe non-conductive bellows 32 in Byrne is to “allow thermal growth ormovement of the heat exchanger in three dimensions” as stated at column2, lines 59-60 of Byrne.

Koiji (English Abstract of JP 58160798, the entire content of which isincorporated herein by reference) discloses a sliding piston ring 5which absorbs the “difference of longitudinal thermal expansions of theinner wall surface of the hole 2 and the circular pipe 4,” as stated inthe English Abstract of Koiji.

Oda (U.S. Pat. No. 4,753,457, the entire content of which isincorporated herein by reference) discloses a non-conductive bellows 40connecting a flange member 53 to a metallic ring 30 in FIG. 1. Thisconfiguration permits that “the heat insulating layer 60 can follow thetube 10 within the range of movement permissible to the [non-conductive]bellows 40, and the gastight sealing properties can be maintained,” asdiscussed at column 6, lines 63-65 of Oda. Note that the heat insulatinglayer 60 of Oda intentionally blocks heat exchange through thenon-conductive bellows 40.

Modine (European Patent Application EP 1878990 A1, the entire content ofwhich is incorporated herein by reference) discloses an elastic sleeve15 connecting a tube 11 to a header 18. This elastic sleeve 15 isconfigured to “allow each tube in a heat exchanger to expand freely andindependently of the other tubes,” as stated at column 1, lines 27-28.

All of the above references Hoffmüller, Neary, Byrne, Koiji, Oda, andModine) are conventional heat exchangers which use non-conductivebellows merely to accommodate the physical movements of heat exchangertubes due to thermal expansion of the tubes (primarily expansion orlengthening along the axial direction of the tubes). Again, the to“non-conductive bellows” indicates that the non-conductive bellows isnot located in a flow path of the external fluid, and therefore is notconfigured to exchange heat between the external fluid and the internalfluid.

These references do not disclose using bellows to pressure compensatethe thermal expansion of an incompressible heat transfer fluid (such asoil), and certainly do not disclose an integrated pressure compensatingheat exchanger. Further, these references do not disclose usingconductive bellows for heat exchange, and do not disclose integratingpressure compensation and heat exchange in a single part.

Accordingly, it would be desirable to provide devices and methods thatovercome the above described problems and drawbacks.

BRIEF DESCRIPTION OF THE INVENTION

According to an embodiment of the present invention, an integratedpressure compensating heat exchanger including an inlet, a conductivebellows, and an outlet is provided. The conductive bellows is configuredto exchange heat between an external fluid located outside of theconductive bellows and an internal fluid passing internally through theconductive bellows. Additionally, the conductive bellows is configuredto compensate for a change in the pressure of at least one of the fluidsby compressing (contracting) in length to change a volume of theconductive bellows.

According to another embodiment of the present invention, an integratedpressure compensating heat exchanger including an inlet, a firstconductive bellows, a first adaptor, a second conductive bellows, asecond adaptor, an outlet, a first guide, a second guide, a preloadspring, and an actuator is provided. The inlet, the first conductivebellows, the first adaptor, the second conductive bellows, the secondadaptor, and the outlet are configured so that an internal fluid flowssequentially through them. The first conductive bellows, the secondconductive bellows, and a smooth portion of the outlet are substantiallyparallel, and are held substantially parallel by the guides. Theactuator is configured to move the first adaptor in a direction parallelto the first and second conductive bellows such that the first andsecond conductive bellows are compressed, and such that the second guideslides along the smooth portion of the outlet while maintaining theparallel configuration of the first and second conductive bellows andwhile compressing the preload spring.

Throughout this specification and claims, the direction of flow of theinternal fluid is arbitrary, and may be reversed at any time. In otherwords, the inlet may serve as an outlet, and an outlet may serve as aninlet.

According another embodiment of the present invention, an integratedpressure compensating heat exchanger including an inlet, a firstconductive bellows, an adaptor, a second conductive bellows, an outlet,and a guide plate is provided. An axial direction of the firstconductive bellows and an axial direction of the second conductivebellows are parallel to each other. The guide plate is configured suchthat a direction normal to the surface of the guide plate issubstantially perpendicular to the axial (longitudinal) directions ofthe first conductive bellows and of the second conductive bellows. Theguide plate is located adjacent to the first conductive bellows and thesecond conductive bellows, such that the first conductive bellows andthe second conductive bellows are prevented from passing through thesurface of the guide plate during compression of the first conductivebellows and the second conductive bellows. Furthermore, the guide platehas orifices configured to facilitate a flow of an external fluidthrough the guide plate. If three or more conductive bellows are used,and if the axes of the three or more conductive bellows are parallel toeach other and are not in the same plane, then the guide plate may becurved to accommodate (conform with) the non-planar orientation of thethree or more conductive bellows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate one or more embodiments and,together with the description, explain these embodiments. In thedrawings:

FIG. 1 is a schematic diagram of a conventional heat exchanger;

FIG. 2 a is a schematic diagram of an integrated pressure compensatingheat exchanger with conductive bellows (in an uncompressedconfiguration);

FIG. 2 b is a schematic diagram of an integrated pressure compensatingheat exchanger with conductive bellows (in a compressed configuration);

FIG. 3 a is a schematic diagram of an integrated pressure compensatingheat exchanger with a piston (in an uncompressed configuration);

FIG. 3 b is a schematic diagram of an integrated pressure compensatingheat exchanger with a piston (in a compressed configuration);

FIG. 4 a is a schematic diagram of an integrated pressure compensatingheat exchanger with guides, a spring, and an actuator (in anuncompressed configuration);

FIG. 4 b is a schematic diagram of an integrated pressure compensatingheat exchanger with guides, a spring, and an actuator (in a compressedconfiguration);

FIG. 5 is a schematic diagram of an integrated pressure compensatingheat exchanger with a guide plate (shown in an uncompressedconfiguration);

FIG. 6 is a schematic diagram of an integrated pressure compensatingheat exchanger assembly with a guide plate (in an uncompressedconfiguration);

FIG. 7 is a schematic diagram of an integrated pressure compensatingheat exchanger assembly with a guide plate (in a compressedconfiguration);

FIG. 8 is a schematic diagram of an electric engine including anintegrated pressure compensating heat exchanger; and

FIG. 9 is a flow chart illustrating a method of using an integratedpressure compensating heat exchanger.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION

The following description of the exemplary embodiments refers to theaccompanying drawings. The same reference numbers in different drawingsidentify the same or similar elements. The following detaileddescription does not limit the invention. Instead, the scope of theinvention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the subject matter disclosed. Thus, theappearance of the phrases “in one embodiment” or “in an embodiment” invarious places throughout the specification is not necessarily referringto the same embodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Throughout these specification and claims, the direction of flow of theinternal fluid is arbitrary, and may be reversed at any time. In otherwords, the inlet may serve as an outlet, and an outlet may serve as aninlet.

Throughout these specification and claims, the term “conductive bellows”indicates that the conductive bellows are configured to exchange heatbetween an internal fluid passing inside the conductive bellows and anexternal fluid passing outside the conductive bellows.

Throughout this specification and claims, sequential orders of parts areoften listed. These sequential orders allow insertion of other partsbetween the listed parts.

FIG. 2 a is a schematic diagram of an integrated pressure compensatingheat exchanger (IPCHE) with conductive bellows (in an uncompressedconfiguration).

In FIG. 2 a, an integrated pressure compensating heat exchanger (IPCHE)with conductive bellows is shown in an uncompressed configuration 30,and includes: an inlet 36, a conductive bellows 38 (uncompressed), andan outlet 40. An internal fluid 6 passes internally through theconductive bellows 38 from left to right. An external fluid 4 passesexternally over the conductive bellows 38 and exchanges heat with theinternal fluid 6 through the walls of the conductive bellows 38. Thefluids may flow by natural convection or may be pumped (forcedconvection).

FIG. 2 b illustrates an integrated pressure compensating heat exchanger(IPCHE) with conductive bellows shown in a compressed configuration 44.In the compressed configuration, the conductive bellows 38 is compressedin an axial (longitudinal) direction resulting in a change in length 46.This compression results in a change of volume of the conductive bellows38. The change in bellows volume for a single bellows is approximatelyequal to the cross sectional area of the conductive bellows 38 times thechange in length 46 (volume=area times length) for an approximatelycylindrical bellows which compresses in an axial direction. Also, FIG. 2b clearly illustrates a decrease in volume of the conductive bellows asthe configuration changes from uncompressed (FIG. 2 a) to compressed(FIG. 2 b).

The decrease in volume of the conductive bellows (“bellows volume”) mayaccommodate (pressure compensate) for: a) an increase in volume of theinternal fluid due to expansion from heating, or b) a decrease in volumeof the internal fluid due to contraction from cooling. Conversely, anincrease in bellows volume may accommodate conditions opposite to thosedescribed above. The exact shape and deformation characteristics of theconductive bellows may be considered for precise calculations.

In one embodiment, the external fluid is oil in a cavity of fixed volumein the body of an electric motor, the internal fluid is a process gas(i.e., a gas that is being compressed by a compressor attached to theelectric motor), and an increase in temperature of the oil results in anincrease of the volume of the oil. This increase in the volume of theoil is pressure compensated (or “absorbed”) by the decrease in thevolume (compression) of the conductive bellows. In other words, theexpanding oil expands into some volume previously occupied by theconductive bellows. In another application, the external fluid is theprocess gas and the internal fluid is oil. Of course, those skilled inthe art would appreciate that the external and internal fluids may bevarious other substances.

As an illustrative calculation, an electric motor may have 600 liters ofoil (V), may experience temperatures ranging from 0 to 120 degreesCelsius (ΔT=120), and may have a diathermic fluid thermal expansioncoefficient of 0.000765 per degree Celsius (k). The change in volume(ΔV) of the oil is calculated as follows: ΔV(oil)=V×ΔT×k. Inserting theabove values yields a change in volume ΔV(oil) of 55 liters.

Further, a bellows may have an effective diameter (D) of 82 mm, a totallength (L) of 470 mm, and a compression change in length (ΔL) of 67% ofthe total length (ΔL=315 mm). The cross sectional area (A) of thebellows is calculated as A=(π×D2)/4 which equals 5278 mm2. The change involume of a single bellows is calculated as ΔV(single bellows)=A×ΔL,which equals 1,662,667 mm3. A liter equals 1,000 cubic centimeters, orequals 1,000,000 mm3. Converting, ΔV(single bellows)=1.66 liters.Therefore, the number of bellows (N) needed to compensate for theexpansion of the oil is calculated as N=ΔV(oil)/ΔV(single bellows) whichequals about 33 bellows.

If design constraints limit the number of bellows to a maximum of 24bellows, then these 24 bellows can only compensate for a ΔV(oil) of 40liters (which is less than the 50 liters discussed above). In this case,one or more other factors may be varied to satisfy this 24 bellowsconstraint. For example: the diameter and/or length of the bellows maybe increased; a small dedicated pressure compensator may be added(preferably internally, inside the oil cavity); the casing of theelectric motor may be redesigned to decrease the volume of oil required;a different oil may be used which is less sensitive to changes intemperature (smaller k); and so forth. The final engineering design is acomplex multi-variable optimization problem, and beyond the scope ofthis discussion.

Additional advantages of the conductive bellows of FIG. 2 include:compact due to integration of pressure compensating and heat exchangingfunctions; excellent heat exchange characteristics due to large surfacearea of bellows (in comparison to conventional tubes); can optionallyincorporate active pressure control (discussed below); and easy toinstall due to flexibility of bellows.

FIG. 3 a is a schematic diagram of an integrated pressure compensatingheat exchanger (IPCHE) with a conductive piston. FIG. 3 a is similar toFIG. 2 a discussed above, except that a conductive piston 42 is usedinstead of a conductive bellows 38 to illustrate an uncompressed(expanded) configuration.

FIG. 3 b is similar to FIG. 2 b discussed above, except that aconductive piston 42 is used instead of a conductive bellows 38 toillustrate a compressed (unexpanded) configuration.

FIG. 4 a is a schematic diagram of an integrated pressure compensatingheat exchanger (IPCHE) with guides, a spring, and an actuator in anuncompressed configuration. Specifically, FIG. 4 a illustrates anintegrated pressure compensating heat exchanger with actuator in anuncompressed configuration 54 includes an inlet 36 admitting an internalfluid 6. The internal fluid 6 passes sequentially through: the inlet 36,a first conductive bellows 38 a, a first U-shaped adaptor 39 a, a secondconductive bellows 38 b, a second U-shaped adaptor 39 b, and an outlet40. The outlet 40 includes a smooth portion substantially parallel withthe first and second conductive bellows 38 a and 38 b.

A first guide 60 and a second guide 61 are configured to link the firstand second bellows to the smooth portion of outlet 40. A preload spring58 is compressively preloaded to push the first guide 60 and the secondguide 61 apart so that the first and second conductive bellows are in anuncompressed configuration. The actuator 62 is connected to the firstU-shaped adaptor 39 a.

FIG. 4 b illustrates an integrated pressure compensating heat exchangerwith actuator (in a compressed configuration) 56. The actuator 62 haspushed the first U-shaped adaptor 39 a to the left, thereby compressingthe first and second conductive bellows. The guide ring 61 slid to theleft along the smooth portion of the outlet 40, while holding andstabilizing the first and second conductive bellows as they arecompressed simultaneously. The actuator 62 may be replaced by orcombined with a position sensor (not shown). The actuator 62 mayactively control a pressure of a fluid, or a pressure differentialbetween the internal fluid and the external fluid.

FIG. 4 b illustrates several novel advantages. First, using twoconductive bellows 38 a and 38 b joined by a first U-shaped adaptor 39 aallows compression to occur without changing the locations of the inlet36 and the outlet 40. Further, this compression may be controlled by thefirst U-shaped adaptor 39 a, which is connected to a single actuator 62.This first U-shaped adaptor 39 a may be described as “mobile,” whereasthe second U-shaped adaptor 39 b may be described as “stationary.” Inthis fashion, a single mobile U-shaped adaptor 39 a effectively controlstwo bellows 38 a and 38 b (which may be described as “paired”).

Second, additional bellows may be added (preferably in pairs) whileretaining this very useful feature of allowing compression withoutchanging the location of the inlet 36 and the outlet 40. See FIG. 5which adds 4 more bellows (adds 2 more pairs of bellows).

Third, the preload spring 58 tends to push the first U-shaped adaptor 39a to the right, and thus tends to push the actuator 62 into theuncompressed position (when the actuator is not actuated), as shown in54. Therefore, the actuator 62 may be a “single action” actuator whichonly exerts a force (leftward in this example) when actuated, and thepreload spring exerts a force (rightward) at all times.

Alternatively, a “double action” actuator may be used to directly pushor pull the first U-shaped adaptor 39 a to the left or to the right inorder to respectively compress or decompress the integrated pressurecompensating heat exchanger (which would eliminate the need for thepreload spring).

FIG. 5 is a schematic diagram of an integrated pressure compensatingheat exchanger (IPCHE) with a guide plate (shown in an uncompressedconfiguration) 64. See FIG. 7 for an illustration of compressed bellowsadjacent to a guide plate.

In FIG. 5, the internal fluid 6 enters an inlet 36, and then passessequentially through: a first conductive bellows 38 a, a first U-shapedadaptor 39 a, a second conductive bellows 38 b, a second U-shapedadaptor 39 b, a third conductive bellows 38 c, a third U-shaped adaptor39 c, a fourth conductive bellows 38 d, a fourth U-shaped adaptor 39 d,a fifth conductive bellows 38 e, a fifth U-shaped adaptor 39 e, a sixthconductive bellows 38 f, a sixth U-shaped adaptor 39 f, and an outlet 40having a long smooth portion parallel and adjacent to the sixthconductive bellows 38.

Arrow 70 indicates a direction of compression. The first, third, andfifth U-shaped adaptors (39 a and 39 c and 39 e located at the left sideof FIG. 5) move in the direction of arrow 70 during compression of thebellows 38. These three U-shaped adaptors 39 a and 39 c and 39 e may bedescribed as “mobile,” because they move during compression (and may beattached to one or more actuators, not shown). These three U-shapedadaptors 39 a and 39 c and 39 e may be connected to a single actuator(not shown), and/or may be held by a guide (not shown) preferablycoupled to the smooth portion of outlet 40. The smooth portion of outlet40 also provides a convenient mounting location for one edge of guideplate 66 (mounts not shown). In FIG. 5, the bellows are uncompressed.See FIG. 7 for an illustration of compressed bellows adjacent to a guideplate.

The sixth U-shaped adaptor 39 f is attached to outlet 40, and thereforeis stable or fixed in position. The second and fourth U-shaped adaptors39 b and d are preferably fixed in position (not shown), but may bemobile.

Alternatively, the sixth U-shaped adaptor 39 f may be omitted, and thenthe outlet 40 would connect directly (not shown) to the sixth conductivebellows, and would point upwards and to the right, instead of downwardsand to the left. A guide plate 66 keeps the bellows 39 in a specificorientation. As shown, guide plate 66 has the curved shape of a portionof the surface of a cylinder, wherein the cylinder has an axialdirection parallel with the axial directions of the conductive bellows38.

The guide plate 66 serves several functions. The interior of thecylinder may contain moving parts (not shown) which may puncture theU-shaped adaptors 39 or the conductive bellows 38. Thus, it is importantto allow the conductive bellows 38 to contract in the direction of thearrow 70 while being restrained from entering the cylinder defined bythe guide plate 66. Further, the inlet 36 and the outlet 40 may be fixedto the guide plate 66.

Additionally, the guide plate 66 may have orifices 68 allowing theexternal fluid 4 to easily pass through and then to transfer heat to theinternal fluid 6 through the bellows 38. The guide plate 66 may haveother shapes (for example, planar instead of cylindrical), and theorifices 68 may be rectangular (for example, orifices resulting from amatrix of wires such as a screen). The guide plate 66 may have noorifices 68, or may have orifices 68 only in certain areas in order todirect the flow of external fluid into a desired flow pattern. The guideplate 66 may also have protrusions (not shown) preventing the firstconductive bellows 38 from touching (scraping against) the secondconductive bellows 38. The guide plate 66 may be bent to create troughs(not shown) being coaxial with and individually guiding each conductivebellows 38.

FIG. 6 is a schematic diagram of an integrated pressure compensatingheat exchanger assembly with a guide plate (in an uncompressedconfiguration) 74. Specifically, FIG. 6 is similar to FIG. 5, exceptthat the integrated pressure compensating heat exchanger is shownsituated in the casing of an electric motor. The interior surface of thecasing defines the exterior surface of a cavity holding an externalfluid such as oil.

FIG. 7 is a schematic diagram of an integrated pressure compensatingheat exchanger assembly with a guide plate (in a compressedconfiguration) 76. FIG. 7 is similar to FIG. 6, except that the bellows38 are compressed. This compression was previously illustrated in thelower portions of FIGS. 2, 3, and 4.

FIG. 8 is a schematic diagram of an electric engine assembly 78including an electric engine 82 and an integrated pressure compensatingheat exchanger 30. The electric engine 82 may be a permanent magnetmotor. Ellipse 80 shows the location of the integrated pressurecompensating heat exchanger 30 inside of an electric engine. FIG. 8 alsoshows part of a compressor 100 that may be integrated with the electricengine 82.

FIG. 9 is a flow chart 84 illustrating a method of using an integratedpressure compensating heat exchanger 30.

First step 86 flows an internal fluid 6 inside of the integratedpressure compensating heat exchanger 30. Second step 88 flows anexternal fluid 4 outside of the integrated pressure compensating heatexchanger 30 to exchange heat with the internal fluid 6. Third step 90decreases a volume of integrated pressure compensating heat exchanger 30proportionally as a volume of the external fluid 4 increases due toincreases in temperature of the external fluid 4, such that theintegrated pressure compensating heat exchanger 30 compresses to acompressed configuration 44.

The decrease in volume of integrated pressure compensating heatexchanger 30 may occur automatically as a pressure of the external fluidincreases and presses harder, or may occur in response to an actuator62.

Similarly, the volume of the integrated pressure compensating heatexchanger 30 may increase as a volume of the internal fluid 4 increases.

It should be understood that this description is not intended to limitthe invention. On the contrary, the exemplary embodiments are intendedto cover alternatives, modifications and equivalents, which are includedin the spirit and scope of the invention as defined by the appendedclaims. Further, in the detailed description of the exemplaryembodiments, numerous specific details are set forth in order to providea comprehensive understanding of the claimed invention. However, oneskilled in the art would understand that various embodiments may bepracticed without such specific details.

Although the features and elements of the present exemplary embodimentsare described in the embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the embodiments or in various combinations with or withoutother features and elements disclosed herein.

This written description uses examples of the subject matter disclosedto enable any person skilled in the art to practice the same, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the subject matter is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims.

1. An integrated pressure compensating heat exchanger comprising: aninlet configured to input an internal fluid; a first conductive bellowsconnected to the inlet, configured to accept the internal fluid from theinlet, configured to transfer heat between the internal fluid and anexternal fluid, and configured to compensate for a pressure bycompressing in length; and an outlet configured to accept the internalfluid from the first conductive bellows and to output the internalfluid.
 2. The integrated pressure compensating heat exchanger of claim1, wherein the internal fluid is process gas, the external fluid is oil,and the first conductive bellows is configured to compress or expand inlength to compensate for a variation in a volume of the internal fluid.3. The integrated pressure compensating heat exchanger of claim 1,further comprising: a first U-shaped adaptor communicatively locatedbetween the first conductive bellows and the outlet; and a secondconductive bellows communicatively located between the first U-shapedadaptor and the outlet, wherein the integrated pressure compensatingheat exchanger is configured such that the internal fluid flowssequentially through the inlet, the first conductive bellows, the firstU-shaped adaptor, the second conductive bellows, and the outlet.
 4. Theintegrated pressure compensating heat exchanger of claim 3, furthercomprising: an actuator mechanically coupled to the first U-shapedadaptor and configured to simultaneously compress the first conductivebellows and the second conductive bellows.
 5. The integrated pressurecompensating heat exchanger of claim 3, wherein the outlet includes asmooth portion substantially parallel with the first conductive bellowsand with the second conductive bellows.
 6. The integrated pressurecompensating heat exchanger of claim 5, further comprising: a firstguide mechanically coupling the smooth portion of the outlet to thefirst conductive bellows and to the second conductive bellows; and asecond guide mechanically coupling the smooth portion of the outlet tothe first conductive bellows and to the second conductive bellows,wherein the second guide is configured to slide along the smooth portionof the outlet as the first conductive bellows and the second conductivebellows compress simultaneously.
 7. The integrated pressure compensatingheat exchanger of claim 6, further comprising: a preloaded springlocated between the first guide and the second guide, and configured topush the second guide away from the first guide, such that the firstconductive bellows and the second conductive bellows are simultaneouslyuncompressed.
 8. An electric engine assembly comprising: an electricengine configured for powering a compressor; and an integrated pressurecompensating heat exchanger located inside of the electric engine andincluding: an inlet configured to input an internal fluid; a firstconductive bellows connected to the inlet, configured to receive theinternal fluid from the inlet, configured to transfer heat between theinternal fluid and an external fluid, and configured to compensate for apressure by compressing in length; and an outlet configured to receivethe internal fluid from the first conductive bellows and to output theinternal fluid.
 9. An integrated electric motor compressor comprising: acompressor; and an electric engine assembly according to claim
 8. 10. Amethod of compensating a pressure and cooling an external fluid using anintegrated pressure compensating heat exchanger, the method comprising:flowing an internal fluid inside of the integrated pressure compensatingheat exchanger; flowing the external fluid outside of the integratedpressure compensating heat exchanger; and decreasing a volume of theintegrated pressure compensating heat exchanger into a compressedconfiguration as a volume of the external fluid increases due to atemperature increase in the external fluid.